Shoe-sewing machine.



A. STROMDAHL.

SHOE SEWING MACHINE.

APPLICATION FILED ocT. 8, 1914.

1, 177,972. Patented Apr. 4,1916.

' I 2 SHEETS-SHEET I.

J 5 ZZ g 1 5,; Mm l1 WMM A. STROMDAHL.

SHOE SEWING MACHINE.

APPLICATION FILED OCT. 8. \914.

1,177,972. I Patented Apr. 4,1916.

2 SHEETS-SHEET 2- THE COLUMBIA PLAI0GRAPH co., WASHINGTON, D. C.

' withthe supporting plate in the tip of the ANDREW STROMDAHI.-,' OF LYNN MASSACHUSETTS.

snon-snwnve MACHINE.

Specification of Letters Patent.

Patented Apr. 4, 1916.

Application filed. October 8 1914. Serial No. 865,731

To all whom it may concern:

Be it known that I, ANDREW STRoMDAnL,

a citizen of the United States, and resident of Lynn, in the county of Essex and State of Massachusetts, have invented new and useful Improvements in Shoe-Sewing Machines, of-which the following is a specification.

My invention relates to McKay shoesewing machines, and consists in improvements by the aid of which the stitching mechanism operates more effectively than in the standard McKay machines heretofore used. In shoe stitching machines of this character, the work is placed upon the horn and rests upon a perforated plate at the tip of the horn, this plate serving as the work support by which the pressure of the presser foot is sustained. At the instant of the stitch cycle when the thread is being drawn up through the work, it has been necessary to relax the pressure of the presser foot so as to relieve the'friction on the thread already engaged by the work, thus to enable the needle in rising to draw the stitch tightly into the shoe. Since the work possesses some flexibility the stitch is thus drawn under a dis.

advantage which would not be encountered if it had been practically possible to main-;

tain the pressure of the presser foot during the drawing of the stitch. .My improvements are characterized by a: device whichenables the pressure of the presser foo-tto be maintained upon the work until the stitch has been completely formed :when the presser foot pressure may then be released only for such periodin the. stitch cycle asis necessary to allow the feed movement to take place. Under the conditions heretofore prevailing, it has also been the practice to start the feed movement of the work almost simultaneously with the release of the needlev from the work itself so as to move that "portion of the thread which is engaged by the last preceding stitch .out of close contact horn and by this means to improve the stitch so'far as possible, inrespect tothe tightness and firmness with which it is drawn into the work. For a portionof the stitch cycle therefore the needle in rising fromthe work men-ts make it ossible to shortentlie peaceof work feed so that this need not take place until after the stitch has been entirely drawn and the needle has come practically to a position of rest at the upper limit of its movement.

In the drawings hereto annexed which illustrate my invention, Figure 1 is a vertical section of the horn of a'McKay sewing machine with my improvements applied thereto;'Fig. 2 is a top plan view on an enlarged scale of the tip of the horn; Fig. 3 is a plan view also on an enlarged scale of a gear plate forming part'of the looper mechanism; Fig. 4 is a vertical sectional view on an enlarged scale of the tip of the born with my improvements attached showing the re lationship of my improvements to the for; mation of a stitch and the feeding of the work; Fig. 5 shows in plan and elevation the button which constitutes a characteristic element of myinvention; Fig. 6 is a side elevation of the feed cam of a McKay machine showing the modifications therein which my improvements make possible; Fig.

cam of the machine showing modifications therein appropriate to my invention; and.

Fig. 8 shows in plan, and elevation a modified form of button.

The general assemblage of my improved work supporting and thread guiding device is shown in Fig. 1. Therein A represents a portion of the framework of v a McKay stitcher, and B the born. The looper L is essentially of the usual characteristics and is rotatably mounted at the tip of the horn. The driving mechanism for the looper is however rearranged in order tosupply the necessary accommodation for my improve ments which relate to the thread guide and work support. The looper L which is. provided with a spur gear annulus L is rotated by means of idler gears L andL which are rotatably mounted upon a plate L, this plate being dovetail-secured into place near the, tip of the born. The idler L is a spur and crown gear which meshes with and is driven by the pinion M formed in the end of the inclined shaft M. The remainder of the looper actuating mechanism is substantially the same as that which has long been in use and need not be described.

Instead of the usual fixed plate at thetip of-the horn, I provide a rotatable button D shown individually inFig. 5 The button is centrally perforated at D and has a ra= dial channel D eXtending from the central perforation to the circumference. Below the top of the button there is formed the neck D and below the neck D the spur gear D. The button is secured in place by means of the projection G (see Fig. 4:) which lies between the top of the button and the projecting annulus formed by the gear teeth D.

The idler spur gear Gr meshes with the gear D and the idler G in turn with the idler Gr. The idler G is a spur and crown gear or spur and bevel gear which meshes with and is driven by the pinion G formed on the end of the inclined shaft G At its lower end shaft G is provided with a gear Gr which meshes with a similar gear G v on the vertical shaft G. The latter shaft is secured to the spur gear C at the base of the horn and this gear is controlled by the spur gear an nulus C through the idler C. The annulus (J is fixed to the bed A of the machine and its gear ratio with the gear C is determined so that no matter to what position the horn B may be turned, the button D at the tip of the horn will remain stationary without rotation and the radial channel D in the top of the button will always point in the direction of the work feed.

It will be perceived by reference to Fig. 4 that when the needle N, having penetrated the work S and engaged a loop of the thread, and having then risen out of the work, that portion of the thread T which has been engaged in the work by the last preceding stitch-formation will lie in the channel D formed in the top of the button D and that consequently although the pressure of the presser foot P be maintained to hold the work firmly against the button D, this pressure will not produce any friction or binding effect upon the thread The needle N, therefore, cooperating w1th the usual thread tension (not shown effectlvely exerts its pull upon the thread T and draws the previously formed loop tightly into the work. The maintenance of the presser foot pressure upon the work enables the stitchmg mechanism to form the stitch and draw the loop much more effectively than is the case when this pressure is relaxed as has been the practice heretofore. Under the conditions furnished by these improvements, there is no necessity for moving the work forward until after the needle has completed its full upward movement, since the thread T is not in any way engaged or restrained by contact with the button D. In order to adapt the McKay machine completely to these improvements, and to give the improvements full opportunity to accomplish their result, it is necessary to redesign the cams which control the presser foot and also the feed, particularly the former. In Fig. 6. which shows the feed controlling camin the Mo- Kay machine, the existing design gives a being controlled by the contour indicated at P As the relaxation or lift of the presser P (Fig. 4) is substantially coterminous with the forward movement of the feed deg F,

the redesigning of the two cams should be,

such that the timing, lift and throw of the two cams'should correspond. Since under the conditions supplied by these improve ments the presser foot P does not relax its hold on the work until the needle has prac tically come to restfor the feed movementto begin, the labor of stitching shoes on a McKay machine is very materially lessened since the machine itself does the work of holding the shoe firmly during all the active portions of the stitch cycle. In addition to this, as above indicated, these improvements enable the stitch to'be formed more firmly and with less wear on the thread or danger of breaking it.

The work-supporting and thread-guiding button. characterized by a thread channel in which the thread may be drawn without encountering friction by being nipped between the button and the shoe, is the foundation on which the improved results rest. The

device of maintaining this button stationary.

in relation to the bed of the machine and thusfmaintaining the thread channel fixed in position to coincide with the direction of work feed. is important. and constitutes part of my improvements in. the preferred form shown in Figs. 1 to inclusive. However. a measurable proportion .of the improvements and advantages ahoveset forth maybe secured with a worl supporting button made as illustrated in Fig. 8. 'This form of button has the central'thread aperture D as usual. but the crown of the button is com-' S posed of. a number of radial ridges Di seoarated b radiallv disposed channels D. The tops of the ridges DKare smoothed. and made as narrow as is consistent with the proper feed movement of the wo k which rests and slides on the button. The button is held in pla e bv means of. the neck D and a flange D a d is preferably l ose and free to otate in it seat at the end of the horn. The thread T will find its wav'into any one of the channels D bv slipping off the ridge D. and when thebutton is. as preferred. loosely and rotatablv mounted, the thread itself willturn the button so as to while the thread is being drawn, so as to guard against accidental nipping of the.

thread between the button and the work, and consequent breakage of thread. lVhile this form of thread-channeled button may be employed, the gear-controlled button will be found practically much the better.

I claim:

1. In a shoe sewing machine, the combination with the rotary horn, stitching mechanism, feed mechanism and presser foot, of a button rotatably mounted in the horn and radially channeled on the side toward the work.

2. In a shoe sewing machine, the combination with the rotary horn, stitching mechanism, feed mechanism, presser foot and presser foot actuating mechanism, of a button rotatably mounted in the horn and radially channeled on the side toward the work, the presser foot mechanism being timed to release pressure after the. stitches are drawn into the work.

3. In a shoe sewing machine, the combination with the horn, stitching mechanism, feed mechanism and presser foot, of a button rotatably mounted in the horn, and a gear train controlling the button to hold it stationary 1n relation to the direction of feed, said button provided with a threadchanuel on the side toward the work.

4-. In a shoe sewing machine, the combination with the rotary horn, stitching mechanism, feed mechanism, and presser 'foot mechanism, of a button rotatably mounted in the horn, a gear train controlling the button to hold it stationary in relation to the direction of feed, said button provided with a thread channel on the side toward the work, the presser foot mechanism being timed to release pressure after the stitches are drawn into the work.

5. In a shoe sewing machine, the combi nation with the rotary horn, stitching mechanism, feed mechanism, andpresser foot mechanism, of a button rotatably mounted in the horn, a gear train controlling the button to hold it stationary in relation to the direction of feed, said button provided with a thread channel on the side toward the work, the presser foot mechanism and feed mechanism being timed to release pressure and advance the work after the stitches are drawn into-the work.

Signed by me at Boston, Massachusetts, this seventh day of October, 1914.

ANDREW STROMDAHL. Witnesses:

ODIN ROBERTS, RICHARD W. HALL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

' Washington, D. C. 

